High magnification high resolution projection lens



nu'wnzr'lhATLUN 111G" RESOLUTION PROJECTION LENS Filed July 2, 1969 2 Sheets-Sheet 1 IMAGE PLAN n 'RI 1; RI g I m 11 FIG I DAVID S. GREY INVENTOR.

ATTORNEY MODULATION Dec. 29, 1970 D. S. GREY HIGH MAGNIFICATION HIGH RESOLUTION PROJECTION LENS Filed July 2, 1969 2 Sheets-Sheet 2 MoouLmbn ram SFER FUNCTIONS m monocnnoumc nouocunonmc on mus FULL FIELD .a SAGITTAL J o rmeeumx.

.5 .4 j I g I .3 .3

I 0 I Z 3 Q S 6 7 8 IO 0 l 2 I 5 6 7 I 9 0 CYCLES/mm CYCLES/mm MODULATION TRANSFER FUNCTONS Mopupanon; N u

3 4 5 6 CYCLES/mm FIG.4

MODULATION z CY SAGITTAL 4 0= TANGENTIAL OLES/mm v FIG. 5 DAVID s. GREY INVENTOR.

ATTORNEY.

United States Patent 3,551,031 HIGH MAGNIFICATION HIGH RESOLUTION PROJECTION LENS David S. Grey, Lexington, Mass., assignor to Bausch &

Lomb Incorporated, Rochester, N.Y., a corporation of New York Filed July 2, 1969, Ser. No. 838,596 Int. 'Cl. G021) 9/64 US. Cl. 350-214 Claims ABSTRACT OF THE DISCLOSURE A high magnification projection lens of substantially 150x having a large relative aperture of substantially f/ 1.2, said lens possessing a high resolution and being substantially diffraction limited particularly at a specified wavelength of the transmitted light, the tangential and sagittal distortion being particularly well corrected as well as less susceptible to the effects of lens tilt.

BACKGROUND OF THE INVENTION In the design of optical systems and projection lenses in particular having a short conjugate and high resolution, it is necessary that the individual lens elements be extraordinarily well optically centered and free from tilt. Even small departures from perfect optical alignment with regards to both tilt and centration of the lens elements results in added difficulties in achieving a satisfactorily high resolution.

High resolution can be achieved partly by excellent optical alignment and partly by such lens qualities inter alia as superior astigmatic and chromatic as well as comatic conditions.

SUMMARY OF THE INVENTION The present invention relates to optical systems having a very short conjugate and more particularly relates to a projection system characterized by a high resolution for advantageous use in microfiche viewing apparatus and the like.

Accordingly, it is an object of the present invention to provide a short conjugate type of projection lens having a superior high resolution.

It is a further object to provide such a device which is not critically sensitive to small amounts of lens tilt and lack of centration.

A further object is to provide such a device wherein the above qualities are achieved along with an excellent state of correction of lens aberrations such as tangential and sagittal astigmatism, chromatic and comatic errors, the design being remarkably free of off-axis asymmetry 'error and flare as evidenced by almost complete absence of phase shift in the computed tangential optical tranfer function (OTF) at the extreme position in the format.

Further objects and advantages will be found in the combination and construction of the details of the invention as set forth in the specification herebelow taken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS fer functions similar to FIG. 2 and phase shift for an- All of the forms of optical systems covered by the present patent application are intended to be used in viewing microfiche transparencies and the like and the systems are all characterized by relatively high resolution atleast as good as 5 lines per millimeter in the projected image and the magnification is times with a relative aperture of substantially f/ 1.2.

The preferred form of the invention is shown in FIG. 1 and numeral 10 generally indicates the optical system comprising a concave plano lens element designated I which is spaced axially at a distance designated S away from a cover plate 14 lying in contact with an object surface 12 to be viewed, said lens having a concave surface designated -R facing the entrant light and a rear surface designated R2 which are separated from each other by a distance designated t The use of the minus sign along with certain R values means that the center of curvature of such a lens surface lies on the object side of said surface.

All of the lens elements in this form of the invention are singlets and the second singlet is designated II. The second lens is spaced rearwardly from lens I by an axial distance designated S the entrant surface being plano and being designated R The rear surface of lens II is a convex surface designated R and it is separated from the front surface R by an axial distance t Spaced at an axial distance S rearwardly from lens II is a double convex lens designated III having a front or entrant surface which is convex and is designated R The rear surface of lens III is convex and is designated -R and it is separated from the front surface thereof by an axial distance t Spaced at an axial distance designated 8., rearwardly from lens 111 is a double concave lens which is designated IV and has formed on the front side thereof a concave surface which is designated -R7. Separated therefrom by an axial distance L, is a concave rear lens surface which is designated R At an axial distance designated S rearwardly of lens IV is a second double convex lens member which is designated V, the front surface thereof being convex and being designated R At a distance designated t axially rearwardly of the front surface is formed a rear convex surface which is designated -R Spaced at an axial distance designated S rearwardly of lens V is a third double convex lens member which is designated VI and a front convex surface is formed thereon which is designated R The rear surface of lens VI is convex and is designated R and it is separated from the front surface R by an axial distance designated t Rearwardly of lens VI is spaced a meniscus negative lens member designated VII, the axial distance between the two lenses being designated S7 and the front surface thereof being concave and being designated R At an axial distance t rearwardly of the front surface is formed a convex lens surface which is designated -R Lenses I to VII are compact and closely spaced near each other, and rearwardly of the front group is spaced a second concave plano lens which is designated VIII at an axial distance therefrom which is designated S Furthermore, in the space S is placed an aperture diaphragm which is designated 11 at a distance which is designated S rearwardly of the lens surface R Lens VIII is characterized by a front concave entrance surface which is designated R and by a plano rear surface R said surfaces being separated from each other by an axial distance designated t,;. I

Spaced rearwarclly from lens VIII at an axial distance S is a double convex lens member which is designated IX and is characterized by a front convex surface which is designated R and a rear convex surface which is designated -R and these surfaces are separated from each other by an axial distance which is designated t The above described lens system 10, it will be noted, has a front Working distance sufliciently large to permit use of a relatively thick cover glass 14 which constitutes a unique and difficult requirement when coupled with the requirement of providing a very high resolution and high magnification. correspondingly, the axial distance S between the lens surface R and the image plane 13 must be large to permit introduction of auxiliary optical equipment such as mirrors and the like whereby the usefulness of the lens system is extended.

In both of the disclosed specific forms of the present invention, the cover plate 14 of FIG. 1 has a constant thickness designated which is substantially .507F where F represents the equivalent focal length of the projection lens system 10.

FIGS. 2 and 3 illustrate graphically the modulation transfer function of the lens system in D light at the long conjugate image plane. It is apparent from these graphs that the image contrast at full field is essentially the same as that on axis in the sagittal fan and is only slightly lower in the tangential fan.

Generically a projection lens 10 which satisfies the objects of the present invention may be provided by the use of the following ranges of values of the constructional data given in the Table I herebelow wherein F designates the equivalent focal length of the lens, R to R designate the curvature of the successive refractive surfaces on the successive singlet lens components which are numbered I to IX in the direction of entrant light, t to represent the axial thicknesses of said lens components, S to S represent the successive axial airspaces between the object and image surfaces which are related to said lens, and m; and 11 represent the refractive index and Abbe number of the glass used in said lens components,

TABLE I 4 TABLE I--Continued For one successful form of the projection lens 10, the

TABLE II Another form of the cally described and spe TABLE II-Continued TABLE III projection lens is mathematicified by the constructional data given in Table III herebelow wherein the designations are the same as above given,

Specific examples in dimensions of millimeters can be computed from the above Tables II and III by substituting a value of 6.17 mm. for F in each table.

It will be perceived from the foregoing that the present invention provides a short conjugate projection lens of magnification which is not subject to deleterious effects of ordinary manufacturing lens tilt by reason of cause of the thorough correction of the usual lens aberrations in addition to the improvement in off-axis asymmetry error and fiare.- The cumulative beneficial effect or result of the above mentioned corrections together with said low curvatures of the lens surfaces is plotted in the graph shown in FIG. 4 wherein modulation is plotted against cycles per millimeter and also in the graph shown in FIG. 5 which corresponds generally to FIG. 3.

Although only certain forms of the invention have been shown and described in detail, other forms are possible and changes may be made in the details of construction without departing from the spirit of the invention as defined in the claims herebelow.

I claim:

1. A projection lens having substantially a 150 magnification and a high resolution and a numerical aperture of substantially f/ 1.2 and having ranges of values of the constructional data as given in the table herebelow wherein F represents the equivalent focal length of said lens,

the curvature of. the successive refractive surfaces numbering from the object side being represented by -R to R and the minus sign used therewith means that the centers of such curvatures lie on the object side of said surfaces, 1 to t represent the axial thickness of nine successive singlet lens elements which are numbered I to IX and whereon said refractive surfaces are formed, S to S represent the successive axial airspaces between the object and image surfaces, and m; and 11 represent the refractive index and Abbe numbers respectively of the glasses used in said elements,

2. A high magnification projection lens of substantially 150x and having a large relative aperture at least as great as f/1.2 and a high resolution, said lens being composed of nine singlet components spaced from each other in optical alignment along an optical axis and designated successively I to IX, the constructional data thereof being set forth in the following table wherein -R to R designate the radii of curvature of the successive refraction surfaces and the minus sign used therewith signifies that the center of curvature of such surface lies on the object side of the apex of said surfaces, S to S designate the successive axial spaces numbering from the object on which said lens is focused, t to 1 designate the axial thicknesses of said components I to IX respectively, and n and 11 represent the refractive index and the Abbe number respectively of the glasses used in said components successively,

3. A high magnification projection lens of substantially x and having a large relative aperture at least as great as f/ 1.2 and a high resolution, said lens being composed of nine singlet components spaced from each other in optical alignment along an optical axis and designated successively I to IX, the constructional data thereof being set forth in the following table wherein R to -R designate the radii of curvature of the successive refractive surfaces and the minus sign used therewith signifies that the center of curvature of such surfaces lies on the object side of the apex of said surfaces, S to S designate the successive axial spaces numbering from the object on which said lens is focused, t; to t designate the axial thicknesses of said components I to IX respectively, and 21 and 1/ represent the refractive index and the Abbe number respectively of the glasses used in said components successively,

9 n (I)=1.72O n (II)=1.69l n (III)=1.691 n (IV)=1.720 n (V)=1.691

n (VI)=1.69l n (VII)=1.72O n (VIII)=l.5l7

n (IX)=1.720 1/(I)=29.3 1 (II)=54.8 v(III)=54.8 v(IV)=29.3 v(V) =54.8 1/(VI) =54.8 1 (VII) =29.3 v(VIII)=64.5 1/(IX) =29.3

4. A high magnification projection lens of substantially 150x and having a large relative aperture at least as great as f/ 1.2 and a high resolution, said lens being composed of nine singlet components spaced from each other in optical alignment along an optical axis and designated successively I to IX, the constructional data thereof being set forth specifically in the following table wherein R to R designate the radii of curvature of the successive refractive surfaces and the minus sign used therewith signifies that the center of curvature of such surfaces lies on the object side of the apex of said surfaces, S to S designate the successive axial spaces numbering from the object on which the lens is focused, t to t designate the axial thicknesses of said components I to IX respectively, and n and 11 represent the refractive index and the Abbe number respectively of the glass used in said components successively,

SCALAR VALUES IN m/m. E.F.L.=6.17 Magnification=150 N.A.=f/1.2

Lens Curvatures Thicknesses Spaces 11 7 S =1.16 R1=12.341 I t =2.848 1.720 29.3

Rz=1 lan Sz=0.671 R =Plano II tz=7.381 1. 601

-R =l0.l02 54.8

S;=.067 R =271.550 III t =3.604 1.691 54.8

Ru=l5.004

S4=.325 -R =15.004 IV t =1.544 1.720 29.3

S =.078 Rg=33.218 V t -2.50 1.691 54.8

S =.002 R 1=27.542 VI lo=2.608 1.091 54.8

S =.443 R1 =28.514 VIT =1.55 1,720 29,3

Sa=31.494 R1 =7.720 VIII ts= 92 1.517 64.5

R =Plano S =6.16 R17=124.748 IX tn=4.177 1.720 29.3

5. A high magnification projection lens of substantially 150x and having a large relative aperture at least as great as f/ 1.2 and a high resolution, said lens being composed of nine singlet components spaced from each other in gptical alignment along an optical axis and designated successively I to IX, the constructional data thereof being set forth specifically in the following table wherein R to R designate the radii of curvature of the successive refractive surfaces and the minus sign used therewith signifies that the center of curvature of such surfaces lies on the object side of the apex of said surfaces, S to S designate the successive axial spaces numbering from the object on which said lens is focused, t, to t designate the axial thicknesses of said components I to IX respectively, and n and v represent the refractive index and the Abbe number respectively of the glasses used in said components successively,

SCALAR VALUES IN m/In. E.F.L.=8.17 Magnification=150X N.A.=f/1.2

Lens Curvatures Thickness Spaces N 1) v S 1.14 I {Rl=12.132 t 3 013 R2= Plano 3 S2=3.798 II R1= Plano 6 3 S .060 In {R =908.959

S4= .707 Iv R 13.787

S5= .669 R =42.911 V -2-434 1. 691 64. 8

Sa= .006 Rn=26.354 VI ie=2.658 1. 691 54. 8v

S7= .235 R13= 27.725 VII. t =1.507 1. 720 29.3

Sa=30.668 R1 7.473 VIII. ts= .890 l. 5167 64. 2

R1a=Plano Sg=6.529 R m 110.938 IX l9=4.079 1. 720 29. 3

References Cited UNITED STATES PATENTS 3,437,403 4/1969 Bird 350-214X JOHN K. CORBIN, Primary Examiner UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 551, 3 Dated December 22, 1970 David S. Grey Inventor-(s) i It is certified that error appears in the above-identified patent and that said Letters Patent are hereby chrrected as shown below:

C01. 6, line m, change ".1961 :6 1.96F line l5,de1e "1.60F line 16, delete 13 .13F line 47 change "2 .32F' to '--"1.60F line 48,change' "2.2 m" to 4.13F line %9,'cha.nge .851 to 2 .32F line 50,change "5.27F to 2.2 lF' line 51,change "3 .961 to 4.851 line 52,change "H.281 to 5.27F line 53,change "7.60F to 3.96F line SLchange "H.511 to 3.281 line 55,change "7.9 41 to 7.60F line 56,change "1.22F to 4.51F line 57,chang "18.0 lF" to 7.9 41 line 58,change "9. 181 to 1.22? line 59,de1ete 451 line 60,change "1.031 to 18.0 lF --;line 61 change ".565F to 9. 181 11ne 62,change ".2 l5F" to 351 line 6 change ".3951 to 1.03F' line 6l,change "A131 to 7 .565F line 66,change ".lMlF" to .395F line 67,

change ".675F" to .413F line 68,change ".18 lF" to .2 45 line 69,change ".107F" to .lMF line 70, change .0101 to .675F line 71,change .0511 to .18 1 line 73 ,change ".0011 to .010F line 7'4, chan%87;.038F" to .0511 line 75,change "L96?" to Q Co1.7,11ne l,change ".971 to .001F line 2,change "13 to .038F line 3,change "1.718" to t .983 betwee lines 3-" insert .97F' c S c. 1.11F"; line ",change "1.689" t 135.0F line 5,chang2 "1.689" to 1.718 line 6, change "1.718" to 1.689 line 8,change "1.689" to 1.718 line 9,chan e "1.718" to 1.689 line 10, change "1.515" to 1.6 9 line 12,change "28 .0" to 1.515 line l3,change "52.0" to 1.718 line 1", change "52.0" to 28.0 line 15,change "28.0" to 52. line 17,change "52.0" to 28 .0 line 18,change "28.0" t 52.0 line 19,change "62.0" to 52.0

-CONTINUED-SEE PAGE 2 FORM PO-HJSO (IO-69) UscOMM-DC 0031c UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 Dated December 9, 97

David S. Grey Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

- SHEET #2 Col. 7, line 21, insert "62 .0 before (VIII) line 22, insert "28.0 4 before (IX) line "7, change "-R6' 2.288F" to --R7 2.288F Col. 8, line as, change 43 2F" to 2. 4321 Co1.l0,in the Table under "Thickness", change "r to t Signed and sealed this 29th day of June 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attestinq Officer Commissioner of Patents FORM PO-105O (10-59] u c 50379. 

